The present invention relates to the coating of metals with a polymer film.
In several applications, it is necessary to coat a metal with a polymer film of low thickness, the metal being in the form of a plate or sheet. The properties of the polymeric material required for such applications are essentially the peel strength, on the one hand, and the strength of the seals produced by hot sealing, on the other hand. The polymeric materials commonly used because of their good properties in these applications are ethylene ionomers, i.e. terpolymers of ethylene, methacrylic acid, and an alkali metal methacrylate or zinc methacrylate. Furthermore, U.S. Pat. No. 4,032,692 discloses a process for coating materials by applying to a substrate a molten terpolymer comprising, for 100 parts by weight, from 70 to 90 parts of ethylene, from 0.5 to 10 parts of an ethylenically unsaturated carboxylic acid amide and from 0.5 to 20 parts of an ethylenically unsaturated carboxylic acid ester.